The Interaction Behind Newton’s Laws of Physics

How did Newton’s Laws of Physics come to be? A simple interaction amongst peers in a public house, and the inspiration one man drew from it.

Three men walk into a bar

On January 24th, 1684, Edmund Halley (of Halley’s Comet fame), Robert Hooke and Sir Christopher Wren (the architect, amongst many other talents) met for refreshments after one of the Royal Society’s weekly meetings.

At some point the conversation turned (by Wren’s prompting) to the cosmological question of of the time: how does the force of gravity change depending on the distance between two objects?

This was important because whilst the basic geometric layout of the solar system was broadly understood, the rationale for the movements of the bodies that lay within it were still unknown.

Hooke, apparently a proud man, claimed that he knew the answer, but refused to share it with the group so that “others trying and failing might know how to value it”. However, whilst the other men admitted to not knowing the answer, the question for Halley struck a chord, and his curiosity (and desire to win the 40 shillings reward Wren laid down) was sparked.

Enter Isaac Newton

In August of the same year, Halley travelled to the University of Cambridge to speak to the then Lucasian Professor of Mathematics, Isaac Newton; a man so eccentric that he once stuck a needle in his own eye to test a hypothesis.

Upon asking Newton whether he might know how to help, the great man responded that he had already calculated the answer (which was an ellipse), but could not find his workings.

The meeting ended with Newton promising to redo the sums and send them to Halley in due course.

In November of the same year Newton provided a nine page manuscript to Halley, who quickly realised that not only had he solved the problem, but also touched upon the fundamental laws of a whole new science; and begged him to continue his work.

In 1687, Newton published the Philosophiæ Naturalis Principia Mathematica, Latin for “Mathematical Principles of Natural Philosophy”; a set of three books that outlined the laws of motion, universal gravitation, and supplied the foundation of classical mechanics. It is to this day considered one of the most important works in the history of science and more broadly, the modern world.